Police budgets are complicated things! Each department may well have its own budget and will spend that as it sees fit.
Just once in a while you might get a quirk like say, a crash investigation department buying a motorbike. They might use it to reconstruct accidents (what speed can I safely take this bend at, what can I see on the road at different points in the reconstruction, etc) they might even wangle with the budget bosses that they need a bike to nip off and take statements on ....
Special constables have a huge budget!! Its all government subsidised! They may well 'buy' a bike.
When this sort of thing happens, that bike is that departments bike. Yes, if you go cap in hand and ask to borrow it for the day then they'll lend it out to another department, but by and large, only they will use it.
Thats the sort of scenario where you get a low milage bike.
Worthy of note, is that most 'response' vehicles are fucking hammered !! I wouldn't buy one !! They may well have been serviced regularly, but fuck .... they don't half get abused!
If you know the history of something (above scenario) then yeah - great buy. But a marked RT of a traffic / interceptor / bike team department ?? Its probably had a pretty hard life !!
Also worthy of note is that peepes think that we get super dooper bikes that are 'special'. yeah we do - they're below the bottom rung of the ladder !!
My marked bike has no electronic suspension, non adjustable front, and a spring on the rear and thats it! They are made to a budget, and are not fancy bits of kit by any stretch of the imagination.
They'd make a good courier bike, or a DSA instructing bike or the like, but if you want pride and joy and all that guff, you're probably better off buying private with a bit more spec and one thats not been thrashed !